FamiStudio - FamiStudio is very simple music editor for the Nintendo Entertainment System or Famicom. It is designed to be easier to use than FamiTracker, but its feature set is also much more limited.

WaveShop - Open source audio editor

SunVox - SunVox is a small, fast and powerful modular synthesizer with pattern based sequencer (tracker).

TwistedWave - TwistedWave is one of the unique audio editors that allow you to edit your music file online without any installation.

Cubasis - Cubasis is Steinberg’s streamlined, multitouch sequencer for the iPad.

Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.